Power-driven cylinder piston pump



R. HAsTlNGs, JR., ErAl. 2,433,812

POWER DRIVEN CYLINDER PISTON PUMP Dec. 30, 1947.

Filed Nov. 4, 1944 iii d m sa@ rJK. 05% u? y ele Us, ad n ,nHrLW IHM .tm @a R j ,MJ [7 au /m Patented Dec. 30, 1947 z,433,s1z roWEn-DnrvENcYLmDER rIs'roN PUMP Russell Hast-ings, Jr., Wellesley, and Bernard B.

Becker, Belmont, Mass., assignors to Lewis- Shepard Company, Watertown,Mass., a corporation of Massachusetts l Application November 4, 1944,semi No. 561,912

(ol. s-15s) 11 claims. 1

This invention relates to improvements in power-driven piston pumps. Oneof the objects of the invention is to provide a pump of extremecompactness and high efficiency which can be produced at lowmanufacturing cost.

A further object of the invention 'is to provide a high speed pump ofsmall size adapted to be driven by low horsepower motors and which willbe capable of developing high pressure to permit its use with compacthydraulic mechanisms which are driven by oil delivered by the pump.

To obtain a high efficiency it has been found desirable to employ apiston type of pump as contrasted with other types, such as gear pumps,and to minimize lost motion, either mechanically or hydraulically, toprovide the chamber of the pump with a short passage for the liquid witha large intake opening to insure complete filling of the pump chamberupon each intake stroke and prompt closing of the intake valve upon thecompression stroke. If the intake valve does not open promptly thecylinder may not completely ll on the intake stroke. This results in theproduction in the cylinder of a, partial'vacuum with loss of volumetriceillciency and also produces eavitation which has a severe erodingaction and produces objectionable loud noise and vibration during theoperation of the pump.

Another object of the invention is to providev a construction in whichsuch defects are avoided.

In order to provide a pump having an intake passage of large area toinsure complete filling of the piston, particularly in pumps of smallsize, the pump embodying the present invention comprises a stationarypiston and a complementary cylinder reciprocably mounted uponitvprovided with a large intake port having' a short passage and acooperating quick-closing valve therefor, instead of a usualconstruction in which the cylinder is stationary and the pistonreciprocable therein, thereby enabling the use of a large intake portand shorter intake passage than would be possible if the valved intakeport were located in the piston.

A further object of the invention is to provide valves for the intakeand outlet ports of the pump, particularly that foi` the intake port,which at the end of each stroke is caused by its own inertia to close atthe proper time without the usual time lag and loss of volumetricemciency which in ordinary pump valves depends upon the flow of theliquid to open and close the valve.

A further object of the invention is to provide the reciprocatingcylinder with means which will cause the inertia of the liquid'upon. theintake stroke of the cylinder to aid in opening the valve and rapidlylling the cylinder. 1 In order words, to provide a cylinder constructionhaving a scooping action which aids atmospheric pressure in filling thecylinder during the intake stroke.

A further object of the invention is to provide y a cylinder with ayoke-shaped pitman connection to diametrically opposite sides of thecylinder and to the actuating mechanism which will minimize the sidestrain which might cause excessive wear between the cylinder wall andthe piston thereby enabling minimum tolerance between the cylinder andpiston with substantially no binding effect.

A further object of the invention is to provide a pump in which thepiston and cylinder may be mounted vertically or at any angle relativelyto the vertical, including upside down, sidewise, with the drive shafteither horizontal or vertical, or in which the drive shaft may berotated in either clockwise or counterclockwise direction.

These and other objects and features of the V'invention will more fullyappear from the following description and the accompanying drawings andwill be particularly pointed out in the claims.

A simple embodiment of the invention is illustrated in the accompanyingdrawings in which the pump is shown as mounted vertically upon the baseof a liquid-containing reservoir with the driving shaft mounted inliquid-tight bearings in the vertical wall, the pump and the end of thedriving shaft being submerged in the liquid.

It will however be understood that the reservoir may be of any suitableconstruction and the pump mounted in any suitable manner so long as theintake port is continuously submerged in the liquid.

In the drawings:

Fig. 1` is a view, showing the reservoir in vertical section andillustrating in elevation the pump piston, the pump cylinder, the motor,and the means operated by the shaft thereof for actuating the pumpcylinder;

Fig. 2 is an enlarged transverse vertical sectional view on line2-2'Fig. 1, viewed from right to left; and,

Fig. 3 is a view similar to Fig. 1 showing the reservoir and pump inhorizontal position and the motor in vertical position as illustratingthe capability of the pump to be mounted upon any desired wall of thereservoir.

In the preferred construction illustrated in the drawings the reservoircomprises a bottom I, sides 3 2 and 2. suitable ends I, and a top orcover l. The reservoir may be of any suitable material to provide anon-leakable chamber provided with an inlet pipe i and suitable meansfor maintaining liquid at a predetermined level within the reservoir, orpreferably full.

a socket in the bottom I of the reservoir. The

socket in the reservoir desirably extends below the end of the pistonextension l and provides a chamber I Il having an outlet conduit IIhaving at its end an enlarged screw threaded wall I2 to receive thescrew threaded end of asuitable conduit I3 for delivering the liquidunder pressure.

The piston 1 has an axial passage Il having at its lower end anenlargement I5 the wall of which provides a valve seat for a preferablyspherical valve ball I6 which is normally supported upon the upper endof a conical coiled spring I1, the

larger lower end of which is seated upon a snap ring I8 which is held ina complementary recess in the inner wall of the piston extension 2 andis located above the chamber 'I0 in the base I.

'I'he upper end of' the piston desirably is provided with a coroidalextension I9 the purpose of which will hereinafter be described. Thecylinder of the pump is reciprocably mounted upon and slidably nts thepiston 1 with a minimum of clearance and is provided at its upper endwith an inwardly extending flange 2I providing a large inlet port 22 thelower wall of which forms a seat for a valve ball 23. The valve ball 23is seated upon the upper end of a conical spiral spring 24 the enlargedcircularlower end of which is seated upon a snap ring 25 which isexpanded into a complementary recess in the wall of the cylinder.

'I'he conical end I9 of the piston is adapted to extend into the spring24 when the cylinder is at the bottom of its stroke, thereby to reduceto a minimum the volume of the chamber at the end of the working strokefor the purpose of assuring the maximum expulsion of any air which may yhave been drawn into the cylinder and which might cause air-binding ofthe Dump. 'I'he inwardly flanged upper end 2I of the cylinder desirablyis provided with a conoidal downwardly and inwardly converging wall 28which during the reciprocation' of the piston upon the intake-strokewill have a scoop-like action and cause the inertia of the liquid in thereservoir to ald in opening the valve and in forcing liquid intothecylinder.

Any suitable means may be provided for reciprocating the cylinder. Inthe preferred construction, in order to permit reciprocation of thecylinder without tendency to bind upon the piston, the cylinder isprovided with bifurcated diametrically opposite bosses 21 having shafts28 extending therethrough vup'on which the lower ends of pitman rods 29and III are respectively mount ed. The upper ends of the pitman rods 2land 30 are mounted respectively upon shafts Il and 32 in the ,bifurcatedends of a yoke Il which is pivotally mounted upon a needle bearing Ilupon an eccentric pin 25 of a driving shaft 38 which is mounted in asuitable liquid-tight bearing I1 in the wall 2 of the reservoir. Byreason of the pivotal mounting of the yoke 23 on the eccentric pin 25 ofthe driving shaft equalized and balanced forces are always appliedthrough the diametrically opposite pitman rods to the cylinder whichwillmaintain accurate reciprocation of the cylinder and reduce to aminimum side strains and consequent binding and wear of the cylinder andpiston.

inasmuch as one of the principal objects of the invention is to providea high speed pump of small size adapted to be driven by a low horsepowermotor and which will be capable of developing high pressure, means foractuating the driving shaft desirably is in the form of an electricmotor 38 which may be conveniently attached to or associated with a wallof the reservoir.

In the preferred construction illustrated herein the wall 2 of thereservoir is sufficiently larger than the area of the reservoir which itencloses and of suitable form, such as shown in Fig. 2, to provide asupport for the electric motor 38. The end of the motor casing issecured thereto by suitable cap screws or bolts 39. In order to insurerigidity of the connection of the motor casing to the wall 2 of thereservoir the head of the lmotor casing desirably is provided with apreferably annular extension 40 which fits and is seated tightly in acomplementary recess in the outer face of the wall 2.

` In the operation of the device, when the pump is in vertical positionas shown in Figs. 1 and 2, the chamber of the reservoir is filled withliquid, or the liquid at least maintained therein at a levelconsiderably above the upper end of the cylinder when the latter is inuppermost position at the.

end of the intake stroke.

Assuming that the cylinder is at the bottom of its stroke, as shown inthe drawings, and the driving shaft rapidly rotating, the upward move;ment of the cylinder causes the inertia of the valve ball 23supplemented by the inertia and pressure of the liquid in the reservoirto displace the valve ball from its seat, thus quickly opening the port22 and permitting the liquid to ilow freely into the chamber of thecylinder.

The downwardly converging wall 26 of the short large passage forming theport in the head of the cylinder also aids in filling the cylindercompletely as it provides a scooplike action which will .more rapidlyfill the cylinder than would be the case in the absence of suchconvergence. When the cylinder is thus completely filled by its upwardmovement, thel downward movement of the cylinder quickly closes thevalve ball 23 for the intake port 22 by reason of the momentum of theball, the pressure of the liquid contained in the cylinder, and thelight spring 24 which backs the valve, so that substantially no liquidescapes from the cylinder. Continued downward movement of the cylinderforces the liquid through the passage I4 of the piston therebydisplacing the valve I6 against the pressure of the light spring I1 andforces the liquid into the chamber I 0 of the socket in the bottom ofthe reservoir and thence through the outlet Il and a conduit I3 throughwhich the liquid under pressure is delivered. Upon the next upwardmovement of the cylinder the valve I6 for the outlet of the piston isquickly closed by the pressure of the liquid in the chamber Ill and thelight spring I1 thereby preventing any appreciable back flow of liquidinto the passage I l of the piston. As a consequence the pump acts at amaximum of efliciency and because of the high speed of the motor, liquidunder high pressure is rapidly delivered to the conduit I 3.

While the invention is illustrated in Figs. l and 2 as comprising a pumpmounted vertically upon the bottom of the reservoir it may be mountedhorizontally upon a suitable vertical wall of the reservoir asillustrated in Figra or suspended in inverted position from the top ofthe reservoir, or in fact in any desired position so long as the liquidin the reservoir continually submerges the inlet port of the cylinder.

It will be readily understood that by virtue of the adaptability of thepump thus to be placed in any desired position the reservoir and pumpmay be readily associated with or incorporated in hydraulic actuatingmechanism of any desirable type and will operate at a maximumeiliciency.

Furthermore by reason of the present invention a pump construction isprovided which can be made of small size and operated by a small motorof low horsepower to discharge liquid under high pressure and is thusadapted to be manufactured at a low cost and to be utilized at a minimumcost of operation because of its efiiciency. Of course, pumps of thischaracter may be made of any desiredv size and capacity. understood thatthe particular embodiment of the invention shown and described herein isof an illustrative character and that various modifications thereof notonly in size and capacity but in form and construction may be madewithin the spirit and scope of the following claims.

Having thus described the invention, what is claimed as new, and desiredto be secured by Letters Patent, is:

1. A high pressure pump construction comprising a liquid-containingreservoir, a pump submerged in said liquid provided with a piston xedlymounted on the base of said reservoir having a vertical passagetherethrough with an outlet port having a valve seat at the lower end ofsaid passage. a spring actuatedball valve normally engaging said Valveseat, a conduit for liquid under pressure communicating with said outletport, a cylinder reciprocably mounted on said piston having a headprovided with an intake port of greater area than that of said passage,a ball check valve for said intake port, a

It will therefore be spring mounted in said cylinder normally holdingthe Valve ball in engagement with said port, said cylinder having anoutwardly diverging wall extending upwardly from said port operable uponupward movement of the cylinder to cause the inertia of said valve bailsupplemented by the inertia of the liquid to aid in quickly displacingthe valve from said port and in forcing the liquid into the cylinder.and means for reciprocating the cylinder rapidly..

2. A high pressure pump constructioncomprislng a liquid-containingreservoir, a piston mounted on the base of said reservoir, and extendinginto the liquid therein, having a shouldered conoidal end portion andprovided with an axial passage having at its lower end an outlet port, acheck valve for said outlet port, a cylinder reciprocably mounted onsaid piston having a head, continuously submerged in the liquid in saidreservoir, provided with an inlet port of greater area than that of saidaxial passage, a valve ball for said intake port, an upwardly andinwardly tapering coiled. spring havin'g its lower end mounted upon thecylinder and its upper end supporting the ball valve and normallycausing it to close said intake port, the construction being such thatupon downward stroke of the cylinder the tapered end of the piston willenter the coiled spring thereby reducing to a minimum the volume of thechamber of the cylinder at the end ofthe working stroke thus assuringmaximum expulsion of air which may have been drawn into the cylinderduring the suction stroke and which might cause air-binding of the pump.

3. A high pressure pump construction compris.. ing a liquid-containingreservoir, a piston mounted on the base of said reservoir, and extendinginto the liquid therein, having a shouldered conoidal end portion andprovided with an axial passage havingat its lower end an outlet port, acheck valve for said outlet port, a cylinder reciprocably mounted onsaid piston having a head, continuously submerged in the liquid in saidreservoir, provided with a short intake port of greater area than thatof the axial passage in said piston having a Wall inclined upwardly andoutwardly thereby shortening the length of said intake passage andenabling the inertia of the liquid upon upward movement of the cylinderrapidly and completely to -ll the cylinder, a ball valve for said intakeport, an upwardly and inwardly tapering coiled spring mounted in saidcylinder with its upper end supporting said ball valve and normallycausing it to close the intake port, the construction being such thatupon downward stroke of the cylinder the tapered end portion of saidpiston will enter the coiled spring and vided with a quick-closing valveand providedl with diametrically outwardly extending bosses, pitmanspivotally connected at their lower ends to said bosses, a driving shafthaving a pin extending eccentricallyv from its end, a yoke mounted onsaid pin provided with lateral extensions complementary to said bossesand in the same plane therewith and provided with means pivotallyconnected to the respective pitmans, means for rotating said drivingshaft, and means for maintaining such level of the liquid in saidreservoiras will continuously submerge said intake port.

5. A high pressure pump construction comprising a liquid-containingreservoir, a pump having a tubular piston mounted therein and having anaxial passage therethrough provided with a quickclosing valved outlet, acylinder reciprocably mounted on said piston having an inlet of greaterarea than that of said passage submerged in the liquid in said reservoirand provided with diametrically opposite journals, means for rapidlyre.. ciprocating said cylinder comprising a shaft rotatable at highspeed, a yoke eccentrically mounted thereon and pitmans symmetricallyconnecting the arms of said yoke respectively to the diametricallyopposite journals of said cylinder to minimize side strain and theconsequent bindv 7 having an inlet of greater area than that of saidpassage and 'provided with diametrically opposite journals in proximityto the end thereof remote from said inlet. means for rapidlyreciprocating said cylinder comprising a high speed mo tor, a yokemounted eccentrically upon the shaft of said motor, and pitmanssymmetrically connecting the arms of said yoke respectively to thediametrically opposite journals of said cylinder.

'1. A high pressure pump construction comprising a liquid-containingreservoir, a pump therein having a. tubular piston rigid with a wall ofthe reservoir and provided with an outlet having a check valve,v acylinder reciprocably mounted on said piston having an intake portsubmerged in the liquid in the reservoir, means for rapidlyreciprocating said'cylinder comprising a shaft driven by high speed, ayoke mounted eccentrically upon the shaft of the motor, and pitmanspivotally connecting the arms of said yoke to said cylinder atdiametrically opposite points adjacent the end Vof the cylinder which isremote from said shaft, thereby to provide connections of maximum lengthand minimum an gularity with respect to theaxis of the cylinder tominimize side strain vand consequent binding and Wear of the cylinderand piston.

8. A high pressure pump construction comprising a liquid-containingreservoir, a pump wholly submerged in the liquid therein laving atubular piston rigid with a wall of said reservoir provided with anoutlet having a check valve, a cylinder tting and slidably mounted onsaid piston means for reciprocating said cylinder at a high speed, saidcylinder having an inwardly converging intake port provided with a checkvalve operable by the inertia of the liquid in front of said intake portupon rapid intake Y inder at a high speed, said cylinder having aninwardlyconverging intake port provided with a check valve operable bythe inertia of the liquid in front of said intake port upon rapid in-vtake movement of the cylinder to produce a pressure which will rapidlyopen said intake valve and quickly and completely ll the cylinder, andmeans for rapidly reciprocatingsaid cylinder having means for applyingbalanced forces to diametrically opposite portions of said cylinderfitting and slidably mounted on said piston having at its end aconically converging inlet port in axial alinement with and of greaterarea than that of said axial passage providing a scoop-likeconstruction, a quick-closing valve for said inlet port, and means forreciprocating the cylinder at such high speed as to cause the inertia ofthe liquid in front of the inlet port upon the intake stroke of thecylinder to exert a pressure which will quickly open the intake valveand rapidly and completely ll the cylinder.

11. A high` pressure pumpconstruction comprising a liquid containingreservoir, a pump wholly submerged in the liquid therein having acylindrical piston with an axial passage therethrough and provided witha relatively larger base stationarily mounted in said reservoir having achamber of larger area than that of said axial passage communicatingtherewith, a quickclosing outlet valve in said chamber, a cylinderfitting and slidably mounted on said piston having at its end aninwardly extending annular flange provided with an inwardly convergingconoidal wall providing a scoop-like intake port of greater area thanand in axial alinement with that of said passage, a spring actuated ballvalve for said inlet port, and means for reciprocating the cylinder at such high speed as to cause the inertia of the liquid in front of theconverging inlet port to exert a pressure which will quickly open theball valve and rapidly and completely lll the cylinder.

' RUSSELL HASTINGS, JR.

BERNARD B. BECKER.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Miller vMay 9, 1876

